mr_ed

I bought an IH S1654 dressed up as a 26' retired uhaul a few weeks ago. I noticed on the drive from Atlanta where I bought it back to northeast NC where I'm stationed that it had a pretty good vibe going on as I came through 35 MPH, then faded around 50 MPH, then came back past 55. Once I got home I checked the hanger bearings (it's got two) and sure enough one was pretty rotted (the truck had been sitting for some time).

I just finished replacing both hanger bearings, along with all the ujoints in the 3 section shaft. I made sure to mark all the shafts so I could index them back in the way they came out. Got it all back together and torqued up and the vibe is still there and worse then ever. I can't even push through 30 mph now cuz it feels like its gonna tear itself apart under there. The hanger bearings and their associated mounting brackets allow for some minute horizontal adjustment, so during install I tweaked them to get the shafts as inline as possible (eyeballing it of course).

Anybody got some pointers on what the issue might be? Mayber a better way to install hanger bearings? Or does this sound like I need to take the shafts in to get completely rebalanced?

Many thanks!

Ed

Hvytrkmech

You probably have a bent drive shaft. I would jack it up and set it on stands and have someone run it to where the vibration is the worst while you watch the shaft spin. I bet you could jump rope with the center section.

Stamey

Another thing I have found, on a few trucks, is bad u-joints will cause this. I called a place to get my driveshaft balanced once, due to a vibe that started around 50 and cleared up at 70. They told me to replace my u-joints before I brought it in to them, because they'd balance it, but would not be responsible if that wasn't the problem.
I pulled my joints, and not one of them was dry, but put new joints in anyway, and the vibe went away.
Check the transmission mount also, if you haven't already.

Chris

mr_ed

Thanks guys I'll do that (jack it and check the trans mounts). all the ujoints are brand spanking new, but if it comes down to it I'll keep that in mind as a last resort.